This is Determinism, which is a very old idea (not to say it's wrong - just that this is a philosophical debate that rages on). There are lots of interesting works written on it versus Free Will.
My main issue with it is it seems to discount random events - and at a quantum level, it seems like there are genuinely random events, like radioactive decay. So it's not really accurate to say there are only two variables, there are really countless ones, and even small changes (like a few atoms splitting here and there) could lead to something like cancer in a friend or relative, having a serious impact on one's life. Still isn't an argument for the existence of free will though.
My main issue with it is it seems to discount random events - and at a quantum level, it seems like there are genuinely random events, like radioactive decay. So it's not really accurate to say there are only two variables, there are really countless ones, and even small changes (like a few atoms splitting here and there) could lead to something like cancer in a friend or relative, having a serious impact on one's life. Still isn't an argument for the existence of free will though.